Perl 
         
        About the Tutorial 
        Perl is a programming language developed by Larry Wall, especially designed for text 
        processing. It stands for Practical Extraction and Report Language. It runs on a 
        variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. 
        This tutorial provides a complete understanding on Perl. 
         
        Audience 
        This reference has been prepared for beginners to help them understand the basic to 
        advanced concepts related to Perl Scripting languages. 
         
        Prerequisites 
        Before you start practicing with various types of examples given in this reference, we are 
        making an assumption that you have prior exposure to C programming and Unix Shell. 
         
        Copyright & Disclaimer 
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                                                                                                                                                      Perl 
                      Table of Contents 
                           About the Tutorial ............................................................................................................................................ i 
                           Audience ........................................................................................................................................................... i 
                           Prerequisites ..................................................................................................................................................... i 
                           Copyright & Disclaimer ..................................................................................................................................... i 
                           Table of Contents ............................................................................................................................................ ii 
                      PART 1: PERL – BASICS ................................................................................................................ 1 
                      1.   Perl ─ Introduction .................................................................................................................................... 2 
                           What is Perl? .................................................................................................................................................... 2 
                           Perl Features .................................................................................................................................................... 2 
                           Perl and the Web ............................................................................................................................................. 3 
                           Perl is Interpreted ............................................................................................................................................ 3 
                      2.   Perl ─ Environment ................................................................................................................................... 4 
                           Unix and Linux Installation .............................................................................................................................. 5 
                           Running Perl .................................................................................................................................................... 6 
                      3.   Perl ─ Syntax Overview ............................................................................................................................. 9 
                           Script Mode Programming .............................................................................................................................. 9 
                      4.   Perl ─ Data Types .................................................................................................................................... 15 
                           Numeric Literals............................................................................................................................................. 15 
                           String Literals ................................................................................................................................................. 16 
                      5.   Perl ─ Variables ....................................................................................................................................... 19 
                           Creating Variables ......................................................................................................................................... 19 
                      6.   Perl ─ Scalars ........................................................................................................................................... 23 
                           Scalar Operations .......................................................................................................................................... 25 
                      7.   Perl ─ Arrays ........................................................................................................................................... 28 
                      8.   Perl ─ Hashes .......................................................................................................................................... 39 
                      9.   Perl ─ If…Else........................................................................................................................................... 45 
                           if statement ................................................................................................................................................... 46 
                           if...else statement .......................................................................................................................................... 48 
                           if...elsif...else statement ................................................................................................................................ 50 
                           unless statement ........................................................................................................................................... 51 
                           unless...else statement .................................................................................................................................. 53 
                           unless...elsif..else statement ......................................................................................................................... 55 
                           switch statement ........................................................................................................................................... 56 
                           The ? : Operator ............................................................................................................................................ 59 
                      10.  Perl ─ Loops ............................................................................................................................................ 61 
                           while loop ...................................................................................................................................................... 62 
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                                                   Perl 
          until loop ....................................................................................................................................................... 64 
          for loop .......................................................................................................................................................... 66 
          foreach loop .................................................................................................................................................. 68 
          do...while loop ............................................................................................................................................... 70 
          nested loops .................................................................................................................................................. 71 
          Loop Control Statements ............................................................................................................................... 74 
          next statement .............................................................................................................................................. 74 
          last statement ................................................................................................................................................ 77 
          continue statement ....................................................................................................................................... 80 
          redo statement .............................................................................................................................................. 82 
          goto statement .............................................................................................................................................. 83 
          The Infinite Loop ............................................................................................................................................ 86 
        11.  Perl ─ Operators ...................................................................................................................................... 87 
          What is an Operator? .................................................................................................................................... 87 
          Perl Arithmetic Operators ............................................................................................................................. 87 
          Perl Equality Operators ................................................................................................................................. 89 
          Perl Assignment Operators............................................................................................................................ 94 
          Perl Bitwise Operators ................................................................................................................................... 96 
          Perl Logical Operators ................................................................................................................................... 98 
          Quote-like Operators ................................................................................................................................... 100 
          Miscellaneous Operators ............................................................................................................................. 101 
          Perl Operators Precedence.......................................................................................................................... 103 
        12.  Perl ─ Date and Time ............................................................................................................................. 106 
          GMT Time .................................................................................................................................................... 107 
          Format Date & Time .................................................................................................................................... 107 
          Epoch time ................................................................................................................................................... 108 
          POSIX Function strftime() ............................................................................................................................ 109 
        13.  Perl ─ Subroutines ................................................................................................................................. 112 
          Define and Call a Subroutine ....................................................................................................................... 112 
          Passing Arguments to a Subroutine ............................................................................................................ 113 
          Passing Lists to Subroutines ........................................................................................................................ 114 
          Passing Hashes to Subroutines .................................................................................................................... 114 
          Returning Value from a Subroutine ............................................................................................................. 115 
          Private Variables in a Subroutine ................................................................................................................ 116 
          Temporary Values via local() ....................................................................................................................... 117 
          State Variables via state() ............................................................................................................................ 118 
          Subroutine Call Context ............................................................................................................................... 119 
        14.  Perl ─ References .................................................................................................................................. 121 
          Create References ....................................................................................................................................... 121 
          Dereferencing .............................................................................................................................................. 122 
          Circular References ...................................................................................................................................... 123 
          References to Functions .............................................................................................................................. 124 
         
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